I can’t believe no one’s mentioned Piers Anthony’s Xanth series, which takes place in a magical, alternate-reality Florida. (Well, I guess the OP did say good fantasy novels. But they weren’t bad books for the adolescent set.)
Also, Terry Brooks’ Magic Kingdom For Sale—SOLD! It’s another pocket-universe type setup (like Xanth), whose entry point is in the USA.
I saw mention of Stephen King’s The Stand and the Dark Tower books, but I think The Talisman, written with Peter Straub, is easily classified as fantasy, and is much more bound to the U.S. than the Dark Tower is. (All right, technically, it was drawn in to the Dark Tower universe, but you know what I mean.)
Perhaps it’s just because Lenny Henry read the audio book, but I was sure that Anansi Boys was set primarily in Britain, with the final action in the Caribbean.
It might be more horror (though I think Clive deserves his own category of “fucked up fantasy”) but Barker’s Coldheart Canyon: A Hollywood Ghost Story and The Great and Secret Show are set unequivocally in America.
As noted above, most of H.P. Lovecraft’s horror-fantasy is set in America, specifically in Lovecraft Country. The British-or-otherwise-non-American equivalent is Campbell Country. The distinction between them illustrates the difference between the Old and New Worlds as fantasy settings. From the latter link:
I recently read the Pelbar Cycle by Paul O. Williams and I thought they were excellent. All of them are sent in North America and are well worth a read.
Awww, someone else posted it? I read the whole thread, too! I thought I’d be first.
And yes, I was being ironic. My mom read me Tolkein as bedtime stories when I was 5 or 6, and I’ve been reading good high-fantasy ever since. Meyers’ tripe is remarkable only in the attention it has garnered from raving-mad fangirls, nothing more.
Here are a few more (I haven’t read the thread thoroughly, so there are probably some repeats).
James P. Blaylock - several books
Philip Wylie - Gladiator
L. Ron Hubbard - Slaves of Sleep, Typewriter in the Sky
James Branch Cabell - I think a couple books are set in America, but I haven’t read the whole Biography
Francis Stevens - several books/stories
Charles G. Finney - The Circus of Dr, Lao
Fritz Leiber - several books/stories
Robert W. Chambers - The Maker of Moons
A. Merritt - Dwellers in the Mirage, Seven Footprints to Satan
Sanders Laubenthal - Excalibur
Peter S. Beagle - A Fine and Private Place